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Can You Drill and Tap Wear Resistant Steel Like JADCO QT Plus ®?

Often our customer’s questions make us pause and realize many people may have the same question. This is a perfect reason to receive our weekly Blog Posts, ‘Wear Plate Wednesday’.

Here is one that became today’s blog post. It was from Jody @ Earth: Can you even drill JADCO QT PLUS ® when the hardness is 500 BHN?

The quick answer is yes you certainly can drill and tap QT PLUS ®.

Which procedure you need to use depends if you are making repairs in the field, or you have access to a machining center.

We will cover both methods, but first a few important points of caution, to prevent you from unknowingly creating problems for yourself.

NEVER ATTEMPT TO USE A PUNCH PRESS TO CREATE HOLES IN JADCO’S QT PLUS ® LIKE YOU DO WITH MILD STEEL.

THE PUNCH WILL SHATTER!

temp-post-image

Here is a photo of a shattered punch that failed trying to punch a hole through ¼” JADCO QT PLUS ® hardened wear plate.

Thankfully no one was injured from sharp metal bits flying through the shop.

First we will cover drilling and tapping using a machining center.
Second we will cover drilling and tapping when it is necessary to make repairs in the field.

Using CNC machining centers, your layout is obviously input into the machine.

Drilling Wear Plate On A Machining Center:

Installing millions of holes in through hardened wear plate since August 1980 has taught us what works. Here is how to get the best results:

  • Obtaining the greatest number of holes comes when using TiN coated solid carbide tooling. This gives you the most efficient method and the greatest quantity of holes; at the lowest cost per hole.

  • Even better results come when using internally cooled bits, where the cutting fluid is sprayed directly onto the surface being machined.

  • When using a machining center, preheating the wear plate is not required.

  • For through hardened, wear resistant steel; use the recommended RPM. Our best results come from using ½ the suggested feed rate.

  • Flood the area with coolant.

  • Unlike when you are machining aluminum, please DO NOT program to ‘Peck’ (to back away the tooling to remove material chips) when machining thru hardened wear steel.

Threading On A Machining Center:

  • Use a TiN coated thread mill.

  • Flood the area with coolant.

When drilling holes for field repairs, there are several critical steps to success:

  • CRITICAL: If you plan to use a magnetic base drill – Always do any welding in this area BEFORE you use the mag-drill. With the high quantity of Nickel, Chrome, Moly, Boron and Titanium in JADCO QT Plus ®, a magnetic base drill will create areas that are highly magnetic. They will remain magnetic long after you finish welding. If you drill before you weld, this magnetic field can create significant welding problems.

  • Layout your hole locations and mark them with soapstone or a marker. Don’t ruin your center punch by attempting to mark your hole locations this way. JADCO QT Plus ® is designed as an impact and abrasion resistant plate. QT Plus ® will fight back and ruin your punch.

  • After you have laid out all locations on the steel, using an oxy-fuel torch; heat each individual hole location until they are orange hot, all the way through the plate thickness. This means it needs to glow orange on the back side of the plate. This slightly anneals the location to be drilled, but remember a bolt will soon live there. IMPORTANT: This is one area where many people attempt to short cut the time required, and do not get the steel hot enough. It will only be more difficult to create the holes. A bit of patience here makes for easier drilling.

  • Allow the hole locations on the plate to air cool to room temp, before you attempt to drill any holes. NOTE: If you try to drill it while it still shows color (heat) from annealing, you will also temper and destroy your drill bit. Let it get back to room temperature before starting to drill.

  • Use a 135 degree split point drill bit with plenty of coolant.

  • Drill QT Plus ® similar to the method used on stainless steel – Half the (RPMs) speed, using twice the pressure. Apply only light pressure, or use high speed; the QT Plus ® material will work harden. Either method will ruin your drill bit.

  • Drill the hole only once with the proper diameter drill bit. NOTE: Do not step drill – starting with a smaller diameter drill bit and re-drilling the same location using a larger drill bit each time. That method is a waste of time and will likely create more problems for yourself.

  • For accurate hole sizes, a handheld drill is not recommended unless there is no other option.

Remember, QT Plus ® can also be formed and welded effectively using the proper alloys and correct weld procedures.

After comprehensive testing, QT Plus ® has been specified by highly respected OEM mining equipment manufacturers as the wear plate they use in their most challenging applications. We know you will also benefit using JADCO QT Plus ®.

Isn’t it time for you to invite a JADCO sales professional to review your current applications before it is too late? When we review what you are currently using, what you have tried and how it worked previously; we can help you achieve real improvements in your process.

Contact your local JADCO professional by calling us at (724) 452-5252 or email us at: info@jadcomfg.com.

We look forward to helping you control your biggest wear related challenges.

If you have questions on working with wear resistant steel, we will be happy to assist your efforts. Simply email us at: info@jadcomfg.com. If we use your question in an upcoming blog post, you will receive a JADCO cap and T-shirt.